- 1. a. Existing or happening at the same time; coincident in time; belonging to the same period, or occurring at the same moment, of time; contemporary; simultaneous.
- b. transf. Relating to or treating of different events or things belonging to the same time or period; involving or indicating contemporaneous or simultaneous occurrence.
- c. synchronous curve (Geom.), a curve which is the locus of the points reached at any instant by a number of particles descending from the same point down a family of curves under the action of gravity.
- 2. a. Recurring at the same successive instants of time; keeping time with; going on at the same rate and exactly together; having coincident periods, as two sets of vibrations or the like. Cf. sense 2d below.
- b. Electr. Applied to alternating currents having coincident periods; also to a machine or motor working in time with the alternations of current. ¶erron. Of uniform velocity.
- c. Computers and Telecommunications. Of apparatus or methods of working: making use of equally spaced pulses that govern the timing of operations.
- d. Of a satellite: rotating round the parent planet at the same rate as the planet rotates. Of an orbit: such that a satellite in it is synchronous.